Flushed drugs pollute water by Ron Seely (site broke the link so I removed it):

An extensive nationwide study by the U.S. Geologic Survey has found evidence of pharmaceuticals including antibiotics and hormonal drugs, such as birth control pills, in surface waters throughout the nation.
…
Whether the presence of drugs in water translates into human health impacts is still being studied. But research has shown that drugs containing hormones such as estrogen are causing changes and deformities in fish and other aquatic creatures.

The World Health Organization indicates that human risk assessments have shown low concentrations of pharmaceuticals in drinking water have a negligible health risk. But WHO points out that long-term exposures have not been evaluated, especially in populations with other illnesses or with compromised immune systems. Also, according to the WHO, antibiotics in water supplies are a potential concern because the most frequently used antibiotics are becoming less effective as the infections they are designed to combat become resistant.

Examining the existing evidence to see if there is a high likelihood of danger is not that tricky (that seems to be no, right now, for Bisphenol A). But determining whether the likelihood of danger is too high in reality (not that has been proved yet) is much more difficult…

“They found that 81 percent of these cases resulted in the prescribing of a drug to treat the problem. Only 7 percent of patients received dietary counseling, and only 22 percent were given behavioral therapies such as psychotherapy or stress management counseling…”